This study concerns the ideas and information that people at different developmental levels have about the inner workings of the body--in this case, the digestive system. It hypothesizes that conceptual functionaing associated with these phenomena is impoverished and distorted because of their affect-laden content (i.e., ideas about the body arouse anxiety that leads to repression and distortion), and because the inner workings of the body are hidden from view and not amendable to handling and manipulation. The study will provide a developmental analysis and examination of sex differences in conceptual functioning as it relates to the internal process of digestion. The study has implications for theory of cognitive development, particularly the nature of cognitive-affective interaction, and for program planning in the field of health education.